The task object corresponding to the Cascade Historian. See locate_task in the Gamma manual.
The name of the history to be queried.
Optional, the start of a desired time range in seconds, expressed as a real number. The default is the first value available.
Optional, the end of a desired time range in seconds, expressed as a real number. The default is the last value available.
The number of values collected by the history between the specified times, if successful. Otherwise returns nil and sets _last_error_ to the error string returned by the Cascade Historian.
This function queries the history for the total number of values available.
This function corresponds to the length command, and the Cogent API function HI_Length.